Vertical Profiles of Fluorescent and Coarse Mode Particle Properties in the Colorado River Basin
MARIA ZAWADOWICZ, Chongai Kuang, Olga Mayol-Bracero, Darielle Dexheimer, Mirtha Salatti, Russell Perkins, Paul DeMott, Jessie Creamean, Zezhen Cheng, Nurun Nahar Lata, Swarup China, Brookhaven National Laboratory
Abstract Number: 475
Working Group: Bioaerosols
Abstract
Bioaerosols—aerosols of biological origin—have wide-ranging atmospheric implications, including acting as ice-nucleating particles (INPs) to trigger ice formation in mixed-phase clouds. The potential impacts of bioaerosols on clouds depends on the vertical extent of biological material, yet vertical profiles of speciated aerosols can be difficult to measure without deploying dedicated bioaerosol samplers on airborne platforms such as an aircraft or a tethered balloon. This project investigated the vertical profiles of atmospheric bioaerosol concentrations during the Atmospheric Radiation Measurement (ARM) Surface-Atmosphere Integrated Laboratory (SAIL) campaign in the Colorado River basin. We deployed a novel, small-footprint fluorescence sensor alongside a Size- and Time-resolved Aerosol Collector (STAC) sampler and a collector for off-line quantification of immersion ice nuclei concentrations (IcePuck) on ARM’s tethered balloon system (TBS) during spring and summer of 2023. We obtained simultaneous vertically resolved profiles of fluorescent aerosol concentrations, accumulation and coarse-mode size distributions, and samples of aerosol for subsequent analysis with high-resolution mass spectrometry and microscopy at the Environmental Molecular Sciences Laboratory (EMSL) for identification of specific particle morphologies. In addition, we also deployed a coarse-mode optical particle counter to measure vertically-resolved size distributions of particles up to 35 μm. Measurements of vertical profiles of coarse-mode particles are rare, yet essential to capture the vertical extent of surface-atmosphere interactions, as the coarse-mode particles tend to be limited to surface sources such as dust or pollen. This presentation will discuss a comprehensive characterization of spring and summertime aerobiome in the Colorado River basin, its vertical extent, and its interactions with clouds as a potential source of INPs.